Chapter: Introduction to IM and Presence Service Integration with Microsoft Exchange

Introduction to IM and Presence Service Integration with Microsoft Exchange

Overview

Microsoft Exchange integration with the
IM and Presence Service allows users to incorporate
their calendar/meeting status in Microsoft Outlook into their availability
status on the
IM and Presence Service.

Deployment

The following sections identify the types of deployments available and
describe each.

WebDAV

WebDav (Web
Distributed Authoring and Versioning) is an extension of HTTP that facilitates
creating, changing, and moving documents on a server as well as editing
properties of a file. WebDAV can be used to access Microsoft Exchange mailboxes
over HTTP connectivity. Each folder, message, calendar event, contact, and so
on, has a URL that can be used to access it. The
IM and
Presence Service can use WebDAV to gather information on calendar
events. WebDAV is deprecated in Microsoft Exchange 2010 and beyond.

Figure 1. Microsoft
Exchange Integration with WebDAV over the IM and Presence Service

Exchange Web
Services

Exchange Web
Services (EWS) is a newer set of web services that allow interaction with
Microsoft Exchange mailboxes and contents over HTTP. EWS provides access to
much of the same data that is made available through Microsoft Outlook. It
provides more services, is more robust, and it is easier to use than WebDAV, as
well as being better able to handle exchange-specific data. EWS moves several
responsibilities from the client computer to the server.

Figure 2. Microsoft
Exchange Integration with the IM and Presence Service over EWS

Microsoft Outlook
Calendaring States on the IM and Presence Service

Microsoft Exchange
integration with the
IM and
Presence Service allows users to incorporate their calendar/meeting
status in Microsoft Outlook into their availability status on the
IM and
Presence Service. The table below shows the reachability mappings,
and how the
IM and
Presence Service correlates the status of meetings (as shown in
Microsoft Outlook calendar) in the availability status of users on the
IM and
Presence Service.

Presence Gateway
Options

You must configure a
Microsoft Exchange Server as a Presence Gateway for calendaring information
exchange on the
IM and
Presence Service. The Presence Gateway to Exchange enables the
IM and
Presence Service node to reflect the availability status of the user
on a per-user basis.

Restrictions and
Limitations

The following are
restrictions and limitations for integrating the
IM and
Presence Service with Microsoft Exchange:

You can either configure
one WebDAV Server or multiple Exchange Web Services (EWS) servers. You can not
mix WebDAV and EWS server types in your deployment.

You can add, update, or
delete one or more EWS servers with no maximum limit. However, the
Troubleshooter on the
Presence
Gateway Configuration window is designed to only verify and report
status of the first 10 EWS servers that you configure.

This release of the
IM and
Presence Service does not support the Exchange autodiscover service.
The autodiscover service assumes that a load-balancing mechanism is already in
place across the Client Access Server (CAS) or servers.